Lighting, Light Fixtures, Ceiling and Exhaust Fans - fluorescent light failure

I tried a search but got no match. So...I've two fluorescent light panels in my bathroom. Some time ago one of the units began to blink and then quit working. I replaced the ballast and tubes in both units. Now, only one will light and then only when it seems the ambient temperature is above a certain temperature. I can sometimes twist the tubes and they may come on with both units. The ends of the tubes in both units glow dimly whenever they have power to the units. I've double checked the connections to the ballast and power lines. It checks out okay. What would cause this to happen and how can I repair the units. I'd rather not replace them if I can avoid it.

Fluorescent fixtures need a good ground to operate reliably. Furthermore, as you've discovered, they work better when it's warmer. If the bulbs have been in less than two weeks, you may find that they will work better as the age a bit.

Fluorescent fixtures need a good ground to operate reliably. Furthermore, as you've discovered, they work better when it's warmer. If the bulbs have been in less than two weeks, you may find that they will work better as the age a bit.

Okay, duly noted. So, should I check my connections again? Is there a ground connection of which I am unaware? I'm using the twist on connectors. Is there a better way to connect the wires? I wired my ballasts just as the old ones were. Is there a way to check the "sockets" where the tubes engage? Do these parts "go bad"? If I had the money, I'd consider pulling these panels down and installing incandescent fixtures, but I'm already $50 into parts and tubes, so I've got to try to get these silly things to work.

In what year was the house built? Do the circuits have grounding wires?

We understand it to have been built in 1959. There are only two wires coming out of the ceiling for the units, one black, one white. These are of course connected to the corresponding ballast wires.